The blue light that emits from your smartphone and laptop screens may seem harmless, but according to new research, it can be toxic for your eyes.

Earlier this week, scientists at the University of Toledo said they’ve uncovered how blue light can lead to macular degeneration, a leading cause of vision loss in the US. Essentially, the light waves contain enough energy to erode the health of your eyes over time.

“It’s no secret that blue light harms our vision by damaging the eye’s retina. Our experiments explain how this happens,” said University of Toledo professor Ajith Karunarathne in a statement.

On the light spectrum, blue light has a shorter wavelength, and thus carries more energy than red, yellow or green light. That extra energy is why blue light can be bad for your eyes. Too much exposure can trigger a toxic reaction that’ll kill the light-sensing photoreceptor cells in your retinas.

“No activity is sparked with green, yellow or red light,” Karunarathne said, noting that the “retinal-generated toxicity” was caused only by blue light.

Another molecule in your retinas normally acts as an antioxidant to prevent eye cells from dying. But as people grow older, their immune system will struggle to keep the cells healthy. As a result, a constant bombardment of blue light may very well speed up someone’s chances of developing macular degeneration.

“Photoreceptor cells do not regenerate in the eye,” said Kasun Ratnayake, a PhD student researcher who also worked on the study. “When they’re dead, they’re dead for good.”

So, how can you protect yourself? Unfortunately, blue light can be hard to avoid. It can come from sunlight and from our smartphones and PCs, which often sit directly in front of our faces. But the researchers say that people should be careful about using their electronics devices in the dark. Doing so can focus the blue light directly into your eyes.

“That can actually intensify the light emitted from the device many, many fold,” Karunarathne told Popular Science. “When you take a magnifying glass and hold it to the sun, you can see how intense the light at the focal point gets. You can burn something.”

People can also consider wearing sunglasses and other eyewear that’s designed to filter out blue light. In the meantime, Karunarathne is exploring whether an eye drop solution can be developed to counter the harmful effects. The scientists detailed their findings in a study published in Scientific Reports last month.